Add test for Orchard wallet note detection.

This tests the following operations:
* add a spending key to the wallet
* add notes from the Orchard bundle component of a transaction to the
  wallet
* detect notes in the wallet that correspond to the spending key
* verify that notes that are not ours are not mistakenly labeled
  as ours

src/Makefile.gtest.include

@@ -59,6 +59,7 @@ zcash_gtest_SOURCES += \
 	gtest/test_zip32.cpp
 if ENABLE_WALLET
 zcash_gtest_SOURCES += \
+	wallet/gtest/test_orchard_wallet.cpp \
 	wallet/gtest/test_paymentdisclosure.cpp \
 	wallet/gtest/test_wallet.cpp
 endif

src/gtest/test_transaction_builder.cpp

@@ -7,6 +7,7 @@
 #include "pubkey.h"
 #include "rpc/protocol.h"
 #include "transaction_builder.h"
+#include "gtest/test_transaction_builder.h"
 #include "utiltest.h"
 #include "zcash/Address.hpp"
 #include "zcash/address/mnemonic.h"
@@ -16,69 +17,6 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
-// Fake an empty view
-class TransactionBuilderCoinsViewDB : public CCoinsView {
-public:
-    std::map<uint256, SproutMerkleTree> sproutTrees;
-
-    TransactionBuilderCoinsViewDB() {}
-
-    bool GetSproutAnchorAt(const uint256 &rt, SproutMerkleTree &tree) const {
-        auto it = sproutTrees.find(rt);
-        if (it != sproutTrees.end()) {
-            tree = it->second;
-            return true;
-        } else {
-            return false;
-        }
-    }
-
-    bool GetSaplingAnchorAt(const uint256 &rt, SaplingMerkleTree &tree) const {
-        return false;
-    }
-
-    bool GetOrchardAnchorAt(const uint256 &rt, OrchardMerkleFrontier &tree) const {
-        return false;
-    }
-
-    bool GetNullifier(const uint256 &nf, ShieldedType type) const {
-        return false;
-    }
-
-    bool GetCoins(const uint256 &txid, CCoins &coins) const {
-        return false;
-    }
-
-    bool HaveCoins(const uint256 &txid) const {
-        return false;
-    }
-
-    uint256 GetBestBlock() const {
-        uint256 a;
-        return a;
-    }
-
-    uint256 GetBestAnchor(ShieldedType type) const {
-        uint256 a;
-        return a;
-    }
-
-    bool BatchWrite(CCoinsMap &mapCoins,
-                    const uint256 &hashBlock,
-                    const uint256 &hashSproutAnchor,
-                    const uint256 &hashSaplingAnchor,
-                    CAnchorsSproutMap &mapSproutAnchors,
-                    CAnchorsSaplingMap &mapSaplingAnchors,
-                    CNullifiersMap &mapSproutNullifiers,
-                    CNullifiersMap saplingNullifiersMap) {
-        return false;
-    }
-
-    bool GetStats(CCoinsStats &stats) const {
-        return false;
-    }
-};
-
 TEST(TransactionBuilder, TransparentToSapling)
 {
     auto consensusParams = RegtestActivateSapling();

src/gtest/test_transaction_builder.h

@@ -0,0 +1,73 @@
+// Copyright (c) 2022 The Zcash developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or https://www.opensource.org/licenses/mit-license.php .
+
+#ifndef ZCASH_GTEST_TEST_TRANSACTION_BUILDER_H
+#define ZCASH_GTEST_TEST_TRANSACTION_BUILDER_H
+
+#include "coins.h"
+
+// Fake an empty view
+class TransactionBuilderCoinsViewDB : public CCoinsView {
+public:
+    std::map<uint256, SproutMerkleTree> sproutTrees;
+
+    TransactionBuilderCoinsViewDB() {}
+
+    bool GetSproutAnchorAt(const uint256 &rt, SproutMerkleTree &tree) const {
+        auto it = sproutTrees.find(rt);
+        if (it != sproutTrees.end()) {
+            tree = it->second;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    bool GetSaplingAnchorAt(const uint256 &rt, SaplingMerkleTree &tree) const {
+        return false;
+    }
+
+    bool GetOrchardAnchorAt(const uint256 &rt, OrchardMerkleFrontier &tree) const {
+        return false;
+    }
+
+    bool GetNullifier(const uint256 &nf, ShieldedType type) const {
+        return false;
+    }
+
+    bool GetCoins(const uint256 &txid, CCoins &coins) const {
+        return false;
+    }
+
+    bool HaveCoins(const uint256 &txid) const {
+        return false;
+    }
+
+    uint256 GetBestBlock() const {
+        uint256 a;
+        return a;
+    }
+
+    uint256 GetBestAnchor(ShieldedType type) const {
+        uint256 a;
+        return a;
+    }
+
+    bool BatchWrite(CCoinsMap &mapCoins,
+                    const uint256 &hashBlock,
+                    const uint256 &hashSproutAnchor,
+                    const uint256 &hashSaplingAnchor,
+                    CAnchorsSproutMap &mapSproutAnchors,
+                    CAnchorsSaplingMap &mapSaplingAnchors,
+                    CNullifiersMap &mapSproutNullifiers,
+                    CNullifiersMap saplingNullifiersMap) {
+        return false;
+    }
+
+    bool GetStats(CCoinsStats &stats) const {
+        return false;
+    }
+};
+
+#endif

src/rust/include/rust/orchard/wallet.h

@@ -82,7 +82,8 @@ bool orchard_wallet_tx_contains_my_notes(
 
 /**
  * Add the specified spending key to the wallet's key store.
- * This will also compute and add the associated incoming viewing key.
+ * This will also compute and add the associated full and
+ * incoming viewing keys.
  */
 void orchard_wallet_add_spending_key(
         OrchardWalletPtr* wallet,

src/wallet/gtest/test_orchard_wallet.cpp

@@ -0,0 +1,75 @@
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "random.h"
+#include "transaction_builder.h"
+#include "utiltest.h"
+#include "wallet/orchard.h"
+#include "zcash/Address.hpp"
+
+#include "gtest/test_transaction_builder.h"
+
+#include <optional>
+
+using namespace libzcash;
+
+OrchardSpendingKey RandomOrchardSpendingKey() {
+    auto coinType = Params().BIP44CoinType() ;
+
+    auto seed = MnemonicSeed::Random(coinType);
+    return OrchardSpendingKey::ForAccount(seed, coinType, 0);
+}
+
+CTransaction FakeOrchardTx(const OrchardSpendingKey& sk, libzcash::diversifier_index_t j) {
+    CBasicKeyStore keystore;
+    CKey tsk = AddTestCKeyToKeyStore(keystore);
+    auto scriptPubKey = GetScriptForDestination(tsk.GetPubKey().GetID());
+
+    auto fvk = sk.ToFullViewingKey();
+    auto ivk = fvk.ToIncomingViewingKey();
+    auto recipient = ivk.Address(j);
+
+    TransactionBuilderCoinsViewDB fakeDB;
+    auto orchardAnchor = fakeDB.GetBestAnchor(ShieldedType::ORCHARD);
+
+    // Create a shielding transaction from transparent to Orchard
+    // 0.0005 t-ZEC in, 0.0004 z-ZEC out, default fee
+    auto builder = TransactionBuilder(Params().GetConsensus(), 1, orchardAnchor, &keystore);
+    builder.AddTransparentInput(COutPoint(uint256S("1234"), 0), scriptPubKey, 50000);
+    builder.AddOrchardOutput(std::nullopt, recipient, 40000, std::nullopt);
+
+    auto maybeTx = builder.Build();
+    EXPECT_TRUE(maybeTx.IsTx());
+    return maybeTx.GetTxOrThrow();
+}
+
+TEST(OrchardWalletTests, TxContainsMyNotes) {
+    auto consensusParams = RegtestActivateNU5();
+    OrchardWallet wallet;
+
+    // Add a new spending key to the wallet
+    auto sk = RandomOrchardSpendingKey();
+    wallet.AddSpendingKey(sk);
+
+    // Create a transaction sending to the default address for that
+    // spending key and add it to the wallet.
+    auto tx = FakeOrchardTx(sk, libzcash::diversifier_index_t(0));
+    wallet.AddNotesIfInvolvingMe(tx);
+
+    // Check that we detect the transaction as ours
+    EXPECT_TRUE(wallet.TxContainsMyNotes(tx.GetHash()));
+
+    // Create a transaction sending to a different diversified address
+    auto tx1 = FakeOrchardTx(sk, libzcash::diversifier_index_t(0xffffffffffffffff));
+    wallet.AddNotesIfInvolvingMe(tx1);
+
+    // Check that we also detect this transaction as ours
+    EXPECT_TRUE(wallet.TxContainsMyNotes(tx1.GetHash()));
+
+    // Now generate a new key, and send a transaction to it without adding
+    // the key to the wallet; it should not be detected as ours.
+    auto skNotOurs = RandomOrchardSpendingKey();
+    auto tx2 = FakeOrchardTx(skNotOurs, libzcash::diversifier_index_t(0));
+    wallet.AddNotesIfInvolvingMe(tx2);
+    EXPECT_FALSE(wallet.TxContainsMyNotes(tx2.GetHash()));
+}